People have been warned to expect dangerous conditions, especially along causeways and coastal roads exposed to the west.

Traffic Scotland said that gusts of 70mph have been recorded on the Forth and Tay road bridges while the Met Office recorded a 59mph gust in Lerwick, Shetland, and a 55mph gust in Glasgow.

Police warned that travel conditions in the worst-hit areas of Scotland could be “hazardous”, with disruption also expected on ferries, rail services, roads and bridges.

FERRY SERVICES

Many ferry services operated by Caledonian MacBrayne, which operates in the west of Scotland, have been cancelled or disrupted, while the Argyll Ferries service between Gourock and Dunoon has been suspended.

There were also disruptions and cancellations on NorthLink Ferries services between Orkney, Shetland and the mainland, while P&O ferries said its Larne and Cairnryan sailings were operating with delays of up to at least two hours, with further disruption expected throughout the day.

RAILWAYS

Train services have be withdrawn on the following routes -

Glasgow Queen Street/ Fort William, Oban, Mallaig

Inverness to Wick and Thurso. There are currently no plans to run alternative transport on these routes with the exception of a replacement bus service which will operate between Inverness and Dingwall, Network Rail and train operator ScotRail announced.

The other lines closed are Ayr to Stranraer, Kilwinning to Ardrossan/Largs, and Dumbarton Central to Helensburgh Central.

Network Rail said it would have hundreds of engineers ready to remove fallen trees and repair damaged equipment.

Users of the Forth Road Bridge have been warned to expect significant disruption as the bridge could be closed to all vehicles except cars throughout the day.

The Skye Bridge and Forth Road Bridge were closed to high-sided vehicles while the Tay Bridge was only open to cars.

SCHOOLS

Western Isles Council said all schools and nurseries there will be closed as the police have advised the public not to travel unless it absolutely necessary.

All depots, libraries, museums and sports facilities in the Western Isles will also be shut.

WEATHER BOMBS EXPLAINED

Weather bombs are violent winds created by very rapidly falling pressure in a frontal depression.

The Met Office, which prefers the term explosive cyclogenesis, said such phenomena were significant for the speed of the pressure drop rather than their destructive power.

They occur where the barometer has fallen by 24 millibars in less than 24 hours.

The so-called Hurricane Bawbag, which hit Scotland three years ago yesterday, was among those given “bomb” status.

The storm triggered the Met Office’s first red weather warning, with 165mph winds over Cairn Gorm and 60,000 homes left without power, but it caused far less damage than had been feared.

In the United States, the Washington Post reported in February 2010 that a weather bomb had “exploded” over the east coast, with winds of up to 94mph and nearly 2ft of snow dumped on Central Park in New York, notching up a record monthly snowfall.

Meteorologist Cindy Day, of Canadian TV station CTV Atlantic, described an east coast storm in December 2011 as a “textbook weather bomb”.

Moving in from Cape Cod, it blanketed New Brunswick with 25cm (10in) of snow and drenched Nova Scotia with 70mm (28in) of rain, amid hurricane-force gusts.

However, some people have taken advantage of the extreme conditions created by such bombs.

Surfer Garrett McNamara broke a world record on a 111ft wave off Portugal caused by storm Jolle in January 2013, in which the pressure dropped by 58 millibars in 24 hours.